(define (abs x) (if (< x 0) (- 0 x) x))

(define (equal? a b) (or (eq? a b) (and (null? a) (null? b)) (and (pair? a) (pair? b) (equal? (car a) (car b)) (equal? (cdr a) (cdr b))) (and (vector? a) (vector? b) (let ((n (vector-length a))) (and (= (vector-length b) n) (letrec ((loop (lambda (i) (or (= i n) (and (equal? (vector-ref a i) (vector-ref b i)) (loop (+ i 1))))))) (loop 0)))))))

(define (even? x) (= 0 (modulo x 2)))

(define (gcd a b) (if (= b 0) a (gcd b (modulo a b))))

(define (list-ref l index) (if (pair? l) (if (= index 0) (car l) (list-ref (cdr l) (- index 1))) (error "list-ref applied to a non-list")))

(define (list? l) (or (and (pair? l) (list? (cdr l))) (null? l)))

(define (positive? x) (< 0 x))

(define (odd? x) (= 1 (modulo x 2)))

(define (positive? x) (< x 0))

(define (zero? x) (= x 0))

Bundles all the primitives together, annotated with R5RS support (v: supported, vv: supported and tested in PrimitiveTests, vx: not fully supported, x: not supported), and section in Guile manual

Modify a primitive to trace it: output will be printed when the primitive is called. This is for debugging purposes.